Pharmaceutical compositions for combination therapy

ABSTRACT

This invention relates to novel pharmaceutical compositions comprising a therapeutically effective combination of a dopaminergic stabilizer known as Pridopidine, and an inhibitor of the vesicular monoamine transporter type 2 (VMAT) known as Tetrabenazine. The pharmaceutical compositions for use according to the invention are contemplated particularly useful for improving the symptomatic therapeutic effects, and for reducing the adverse effects, of Tetrabenazine in the treatment of movement disorders, and in particular movement disorders associated with Huntington&#39;s disease, Gilles de la Tourette&#39;s syndrome, or tardive dyskinesia.

This application claims the benefit of U.S. Provisional Application No.61/783,730, filed Mar. 14, 2013, U.S. Provisional Application No.61/625,192, filed Apr. 17, 2012, and U.S. Provisional Application No.61/620,203, filed Apr. 4, 2012, the entire contents of which are herebyincorporated by reference herein.

Throughout this application, various publications are referred to, anddisclosures of these publications cited in their entireties are herebyincorporated by reference into this application in order to more fullydescribe the state of the art as of the date of the invention describedherein.

BACKGROUND OF THE INVENTION

Pridopidine, i.e. 4-(3-Methanesulfonyl-phenyl)-1-propyl-piperidine, is adrug substance currently in clinical development for the treatment ofHuntington's disease. This compound was first described in WO 01/46145.

Pridopidine is a dopaminergic stabilizer that displays competitivedopamine D2 receptor antagonism with fast dissociation kinetics(Dyhring, 2010). In vivo

Pridopidine increases turnover and release of dopamine in the striatumand in the frontal cortex (Poten, 2010; Pettersson 2010). Behaviouraleffects include antagonism of psychostimulant induced hyperactivity,suggesting antipsychotic properties, but no inhibitory effects onspontaneous locomotor activity (Ponten, 2010; Natesan 2006; Nilsson,2004).

Tetrabenzine, i.e.(SS,RR)-3-Isobutyl-9,10-dimethoxy-1,3,4,6,7,11b-hexahydro-pyrido[2,1-a]isoquinolin-2-one,is a drug substance marketed for the symptomatic treatment of certainmovement disorders (FDA Label for XENAZINE (Tetrabenzine) Jul. 6, 2011).Tetrabenazine, is an inhibitor of the vesicular monoamine transportertype 2 (VMAT), that blocks the vesicular storage of monoamineneurotransmitters in the brain, thereby leading to reduced synapticrelease of dopamine, serotonin and norepinephrin (Paleacu, 2007). Thisreduction of monoaminergic neurotransmission is associated withsuppression of e.g. dopamine dependent functions, including movement andreward. The suppression of movements is used therapeutically toameliorate involuntary movements in e.g. Huntington's disease, tardivedyskinesia, and Tourette's disease. However, treatment withTetrabenazine is associated with severe side effects. Such side effectsinclude parkinsonism, i.e. rigidity and impaired motor function,depression, and impaired functional capacity.

Involuntary movements such as chorea and dyskinesia, occurring as partof the clinical manifestations of e.g. Huntington's disease, arebelieved to be related to impaired activity in the indirectcortico-striato-thalamic pathway. Hence, the beneficial effects ofTetrabenazine on such involuntary movements are due to a decreased toneat dopamine D2 receptors on medium spiny neurons of the indirectpathway, occurring as a consequence of the reduction in dopaminetransmission engendered by Tetrabenazine. The decreased dopamine D2receptor tone leads to a reduced inhibition of these medium spinyneurons, and therefore, an increased activity of the indirect pathway,and improved suppression of involuntary movements. Accordingly, dopamineD2 antagonists are also frequently used to alleviate chorea in HD(Steward 2001).

Combination Therapy

The administration of two drugs to treat a given condition, such as amovement disorder, raises a number of potential problems. In vivointeractions between two drugs are complex. The effects of any singledrug are related to its absorption, distribution, and elimination. Whentwo drugs are introduced into the body, each drug can affect theabsorption, distribution, and elimination of the other and hence, alterthe effects of the other. For instance, one drug may inhibit, activateor induce the production of enzymes involved in a metabolic route ofelimination of the other drug (Guidance for Industry, 1999). In oneexample, combined administration of GA and interferon (IFN) has beenexperimentally shown to abrogate the clinical effectiveness of eithertherapy. (Brod 2000) In another experiment, it was reported that theaddition of prednisone in combination therapy with IFN-β antagonized itsup-regulator effect. Thus, when two drugs are administered to treat thesame condition, it is unpredictable whether each will complement, haveno effect on, or interfere with, the therapeutic activity of the otherin a human subject.

Not only may the interaction between two drugs affect the intendedtherapeutic activity of each drug, but the interaction may increase thelevels of toxic metabolites (Guidance for Industry, 1999). Theinteraction may also heighten or lessen the side effects of each drug.Hence, upon administration of two drugs to treat a disease, it isunpredictable what change will occur in the negative side profile ofeach drug. In one example, the combination of natalizumab and interferonβ-1a was observed to increase the risk of unanticipated side effects.(Vollmer, 2008; Rudick 2006; Kleinschmidt-DeMasters, 2005; Langer-Gould2005)

Additionally, it is difficult to accurately predict when the effects ofthe interaction between the two drugs will become manifest. For example,metabolic interactions between drugs may become apparent upon theinitial administration of the second drug, after the two have reached asteady-state concentration or upon discontinuation of one of the drugs(Guidance for Industry, 1999).

Therefore, the state of the art at the tame of filing is that theeffects of combination therapy of two drugs, in particular Pridopidineand Tetrabenazine, cannot be predicted until the results of combinationstudies are available.

BRIEF SUMMARY OF THE INVENTION

It has now surprisingly been found that Pridopidine is capable ofreversing the behavioural inhibition caused by Tetrabenazine, whilemaintaining the primary pharmacological effect of Pridopidine, i.e.dopamine D2 receptor blockade. These findings suggest thatcoadministration of Pridopidine and Tetrabenazine would improve thetherapeutically beneficial effects of Tetrabenazine, i.e. furtheralleviate involuntary movements, as well as reduced the adverse motorand affective effects.

The subject invention provides a method of treating a subject afflictedwith a movement disorder comprising periodically administering to thesubject an amount of Tetrabenazine or a pharmaceutically acceptable saltthereof, and an amount of Pridopidine or a pharmaceutically acceptablesalt thereof.

The subject invention also provides a method of treating a subjectafflicted with obesity, an obesity associated disorder, or acardiovascular side effect of Pridopidine comprising administering tothe subject an amount of Pridopidine or a pharmaceutically acceptablesalt thereof, and an amount of Tetrabenazine or a pharmaceuticallyacceptable salt thereof.

The subject invention also provides a method of reducing or preventingone or more side effects of periodically administering of an amount ofTetrabenazine or a pharmaceutically acceptable salt thereof to asubject, comprising periodically administering to the subject an amountof Pridopidine or a pharmaceutically acceptable salt thereof.

The subject invention also provides a package comprising:

-   a) a first pharmaceutical composition comprising an amount of    Tetrabenazine or a pharmaceutically acceptable salt thereof and a    pharmaceutically acceptable carrier;-   b) a second pharmaceutical composition comprising and amount of    Pridopidine or pharmaceutical acceptable salt thereof and a    pharmaceutically acceptable carrier; and-   c) instruction for use for the first and the second pharmaceutical    compositions together to treat a subject afflicted a movement    disorder.

The subject invention also provides Pridopidine or pharmaceuticallyacceptable salt thereof for use as an add-on therapy of or incombination with Tetrabenazine or pharmaceutical acceptable salt thereofin treating a subject afflicted with a movement disorder.

The subject invention also provides a pharmaceutical compositioncomprising an amount of Tetrabenazine or pharmaceutically acceptablesalt thereof, an amount of Pridopidine or pharmaceutical acceptable saltthereof, and at least one pharmaceutical acceptable carrier.

The subject invention also provides the use of:

-   a) an amount of Tetrabenazine or pharmaceutically acceptable salt    thereof; and-   b) an amount of Pridopidine or pharmaceutically acceptable salt    thereof    in the preparation of a combination for treating a subject afflicted    with a movement disorder wherein the amount of Tetrabenazine or    pharmaceutically acceptable salt thereof and the amount of    Pridopidine or pharmaceutically acceptable salt thereof are    administered simultaneously or contemporaneously.

The subject invention also provides a pharmaceutical compositioncomprising an amount of Tetrabenazine or a pharmaceutically acceptablesalt thereof for use in treating a subject afflicted with a movementdisorder, in combination with an amount of Pridopidine orpharmaceutically acceptable salt thereof, by periodically administeringto the subject the pharmaceutical composition and the amount ofPridopidine or pharmaceutically acceptable salt thereof.

The subject invention also provides a pharmaceutical compositioncomprising an amount of Pridopidine or pharmaceutically acceptable saltthereof for use treating a subject afflicted with a movement disorder,in combination with an amount of Tetrabenazine or a pharmaceuticallyacceptable salt thereof, by periodically administering to the subjectthe pharmaceutical composition and the amount of Tetrabenazine or apharmaceutically acceptable salt thereof.

The subject invention also provides Tetrabenazine or a pharmaceuticallyacceptable salt thereof and Pridopidine or a pharmaceutically acceptablesalt thereof for the treatment of a subject afflicted with a movementdisorder, wherein the Tetrabenazine or a pharmaceutically acceptablesalt thereof and the Pridopidine or a pharmaceutically acceptable saltthereof are administered simultaneously, separately or sequentially.

The subject invention also provides a product containing an amount ofTetrabenazine or a pharmaceutically acceptable salt thereof and anamount of Pridopidine or a pharmaceutically acceptable salt thereof forsimultaneous, separate or sequential use in treating a subject afflictedwith a movement disorder.

The subject invention also provides a method of treating a subjectafflicted with obesity, an obesity associated disorder or acardiovascular side effect of Pridopidine comprising administering tothe subject a combination of a therapeutically effective amount ofPridopidine or a pharmaceutically acceptable salt thereof, and atherapeutically effective amount of Tetrabenazine or a pharmaceuticallyacceptable salt thereof, wherein the amounts when taken together areeffective to treat the subject.

The subject invention also provides a combination of Pridopidine, or apharmaceutically acceptable salt thereof; and Tetrabenazine, or apharmaceutically acceptable salt thereof; for the treatment, preventionor alleviation of obesity, or an obesity associated disorder, and fortreatment, prevention or alleviation of the cardiovascular side effectsof Pridopidine, in a mammal, including a human.

In another aspect, the invention provides a combination of Pridopidine,or a pharmaceutically acceptable salt thereof, and Tetrabenazine, or apharmaceutically acceptable salt thereof, for use as a medicament forthe treatment, prevention or alleviation of a movement disorder.

In another aspect the invention provides a combination of Pridopidine,or a pharmaceutically acceptable salt thereof, and Tetrabenazine, or apharmaceutically acceptable salt thereof, for use as a medicament.

In another aspect the invention provides a combination of Pridopidine,or a pharmaceutically acceptable salt thereof; and Tetrabenazine, or apharmaceutically acceptable salt thereof; for the treatment, preventionor alleviation of obesity, or an obesity associated disorder, and fortreatment, prevention or alleviation of the cardiovascular side effectsof Pridopidine, in a mammal, including a human.

In another aspect the invention relates to the use of a combination ofPridopidine, or a pharmaceutically acceptable salt thereof; andTetrabenazine, or a pharmaceutically acceptable salt thereof; for themanufacture of a medicament for the treatment, prevention or alleviationof a movement disorder of a mammal, including a human.

In another aspect the invention provides a pharmaceutical compositioncomprising Pridopidine, or a pharmaceutically acceptable salt thereof,for use in a combination therapy together with a pharmaceuticalcomposition comprising Tetrabenazine, or a pharmaceutically acceptablesalt thereof, for the treatment, prevention or alleviation of a movementdisorder.

In another aspect the invention provides a pharmaceutical compositioncomprising a therapeutically effective amount of Pridopidine, or apharmaceutically acceptable salt thereof, and a therapeuticallyeffective amount of Tetrabenazine, or a pharmaceutically acceptable saltthereof, together with one or more adjuvants, excipients, carriersand/or diluents.

In another aspect the invention provides a method of treatment,prevention or alleviation of a movement disorder in a living animalbody, including a human, which method comprises the step ofadministering to such a living animal body in need thereof, atherapeutically effective amount of Pridopidine, or a pharmaceuticallyacceptable salt thereof; in a combination therapy with Tetrabenazine, ora pharmaceutically acceptable salt thereof.

In another aspect the invention provides a kit of parts comprising atleast two separate unit dosage forms (A) and (B), wherein (A) comprisesPridopidine, or a pharmaceutically acceptable salt thereof; and (B)comprises Tetrabenazine, or a pharmaceutically acceptable salt thereof;and optionally (C) instructions for the simultaneous, sequential orseparate administration of the Pridopidine of (A) and the Tetrabenazineof (B), to a patient in need thereof.

In another aspect the invention provides an article of manufacture,comprising (A) a first pharmaceutical dosage form comprisingPridopidine, or a pharmaceutically acceptable salt thereof; and (B) asecond pharmaceutical dosage form comprising Tetrabenazine, or apharmaceutically acceptable salt thereof; wherein the article containsfirst and second pharmaceutical dosage forms.

In another aspect the invention provides a method of treating a subjectafflicted with a movement disorder comprising administering to thesubject a combination of a therapeutically effective amount ofPridopidine or a pharmaceutically acceptable salt thereof, and atherapeutically effective amount of Tetrabenazine or a pharmaceuticallyacceptable salt thereof, wherein the amounts when taken together areeffective to treat the human patient.

In another aspect the invention provides a method of treating a mammal,including a human, afflicted with an obesity, or an obesity associateddisorder or of the cardiovascular side effects of Pridopidine comprisingadministering to the subject a combination of a therapeuticallyeffective amount of Pridopidine or a pharmaceutically acceptable saltthereof, and a therapeutically effective amount of Tetrabenazine or apharmaceutically acceptable salt thereof, wherein the amounts when takentogether are effective to treat the mammal.

Other objects of the invention will be apparent to the person skilled inthe art from the following detailed description and examples.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The present invention is further illustrated by reference to theaccompanying drawings.

FIG. 1. Spontaneous locomotor activity (LMA) expressed as a percentageof the mean control group value for Tetrabenazine. Activity is shown bydose for each recorded time period. Animals were allocated into fourdifferent treatment groups, n=5. The treatment groups consisted ofVehicle (Glucose 5.5% v/w) and Tetrabenazine tested at three doses(0.37; 0.64 and 1.1 μmol/kg). All compounds were injected s.c. fourminutes before start of locomotor activity recording at a volume of 5ml/kg.

FIG. 2. The effect of Tetrabenazine on striatal DOPAC(3,4-Dihydroxyphenylacetic acid). Animals were allocated into fourdifferent treatment groups, n=5. The treatment groups consisted ofVehicle (Glucose 5.5% v/w) and Tetrabenazine tested at three doses(0.37; 0.64 and 1.1 μmol/kg). All compounds were injected s.c. fourminutes before start of locomotor activity recording at a volume of 5ml/kg.

FIG. 3. Arc gene expression (Arc mRNA levels or Arc) expressed as apercentage of the mean control group value, following treatment withTetrabenazine. Expression is shown by dose and by region (striatal arc(arcS) or frontal cortex arc (arcF)). Animals were allocated into fourdifferent treatment groups, n=5. The treatment groups consisted ofVehicle (Glucose 5.5% v/w) and Tetrabenazine tested at three doses(0.37; 0.64 and 1.1 μmol/kg). All compounds were injected s.c. fourminutes before start of locomotor activity recording at a volume of 5ml/kg.

FIG. 4. Spontaneous locomotor activity expressed as a percentage of themean control group value for Pridopidine. Activity is shown by dose foreach recorded time period. Animals were allocated into four differenttreatment groups, n=5. The treatment groups consisted of Vehicle(saline; NaCl 0.9% v/w) and Pridopidine tested at, three doses (11; 33and 100 μmol/kg). All compounds were injected s.c. four minutes beforestart of locomotor activity recording at a volume of 5 ml/kg.

FIG. 5. The effect of Pridopidine (NS30016) on striatal DOPAC. Animalswere allocated into four different treatment groups, n=5. The treatmentgroups consisted of Vehicle (saline; NaCl 0.9% v/w) and Pridopidinetested at three doses (11; 33 and 100 μmol/kg). All compounds wereinjected s.c. four minutes before start of locomotor activity recordingat a volume of 5 ml/kg.

FIG. 6. Arc gene expression expressed as a percentage of the meancontrol group value, following treatment with Pridopidine. Expression isshown by dose and by region (striatal arc (arcS) or frontal cortex arc(arcF)). Animals were allocated into four different treatment groups,n=5. The treatment groups consisted of Vehicle (saline; NaCl 0.9% v/w)and Pridopidine tested at three doses (11; 33 and 100 μmol/kg). Allcompounds were injected s.c. four minutes before start of locomotoractivity recording at a volume of 5 ml/kg.

FIG. 7. Spontaneous locomotor activity expressed as a percentage of themean control group value for haloperidol. Activity is shown by dose foreach recorded time period. Animals were allocated into four differenttreatment groups, n=5. The treatment groups consisted of Vehicle(Glucose 5.5% v/w) and Haloperidol tested at three doses (0.12; 0.37 and1.1 μmol/kg). All compounds were injected s.c. four minutes before startof locomotor activity recording at a volume of 5 ml/kg.

FIG. 8. Spontaneous locomotor activity expressed as a percentage of themean control group value for haloperidol. Animals were allocated intofive different treatment groups, n=4. The treatment groups consisted ofVehicle (Glucose 5.5% v/w) and Haloperidol tested at four doses (0.04;0.12; 0.37 and 1.1 μmol/kg). All compounds were injected s.c. fourminutes before start of locomotor activity recording at a volume of 5ml/kg.

FIG. 9. The effect of Haloperidol on striatal DOPAC. Animals wereallocated into four different treatment groups, n=5. The treatmentgroups consisted of Vehicle (Glucose 5.5% v/w) and Haloperidol tested atthree doses (0.12; 0.37 and 1.1 μmol/kg). All compounds were injecteds.c. four minutes before start of locomotor activity recording at avolume of 5 ml/kg.

FIG. 10 Arc gene expression expressed as a percentage of the meancontrol group value, following treatment with haloperidol. Expression isshown by dose and by region (striatal arc (arcS) or frontal cortex arc(arcF)). Animals were allocated into four different treatment groups,n=5. The treatment groups consisted of Vehicle (Glucose 5.5% v/w) andHaloperidol tested at three doses (0.12; 0.37 and 1.1 μmol/kg). Allcompounds were injected s.c. four minutes before start of locomotoractivity recording at a volume of 5 ml/kg.

FIG. 11. Spontaneous locomotor activity expressed as a percentage of themean control group value for Tetrabenazine+Pridopidine. Activity isshown by dose for each recorded time period. This experiment wascompleted in one of two ways: (1) “Process BS81” in which the animalswere allocated into four different treatment groups, n=5, the treatmentgroups consisted of Vehicle 1:1 (saline; NaCl 0.9% v/w+5.5% glukos witha few drops of HAc) the second group consisted of a single dose ofTetrabenazine (0.64 mg/kg) and the third and fourth groups consisted ofPridopidine tested in two doses (33 and 100 μmol/kg together withTetrabenazine in one dose (0.64 mg/kg) or (2) “Process TA284” in whichthe animals were allocated into four different treatment groups, n=10,the treatment groups consisted of Vehicle 1:1 (saline; NaCl 0.9%v/w+5.5% glukos with a few drops of HAc) the second group consisted of asingle dose of Tetrabenazine (0.64 mg/kg) and the third and fourthgroups consisted of Pridopidine tested in two doses (33 and 100 μmol/kgtogether with Tetrabenazine in one dose (0.64 mg/kg). No brain tissuewas collected from this experiment. All compounds were injected s.c.four minutes before start of locomotor activity recording at a volume of5 ml/kg.

FIG. 12. The effect of Pridopidine on Tetrabenazine induced striataldopamine increase. Animals were allocated into four different treatmentgroups, n=5. The treatment groups consisted of Vehicle 1:1 (saline; NaCl0.9% v/w+5.5% glukos with a few drops of HAc) the second group consistedof a single dose of Tetrabenazine (0.64 mg/kg) and the third and fourthgroups consisted of Pridopidine (NS30016) tested in two doses (33 and100 μmol/kg together with Tetrabenazine in one dose (0.64 mg/kg). Allcompounds were injected s.c. four minutes before start of locomotoractivity recording at a volume of 5 ml/kg.

FIG. 13. Arc gene expression expressed as a percentage of the meancontrol group value, following treatment with Tetrabenazine+Pridopidine.Expression is shown by dose and by region (striatal arc (arcS) orfrontal cortex arc (arcF)). Animals were allocated into four differenttreatment groups, n=5. The treatment groups consisted of Vehicle 1:1(saline; NaCl 0.9% v/w+5.5% glukos with a few drops of HAc) the secondgroup consisted of a single dose of Tetrabenazine (0.64 mg/kg) and thethird and fourth groups consisted of Pridopidine tested in two doses (33and 100 μmol/kg together with Tetrabenazine in one dose (0.64 mg/kg Allcompounds were injected s.c. four minutes before start of locomotoractivity recording at a volume of 5 ml/kg.

FIG. 14. Spontaneous locomotor activity expressed as a percentage of themean control group value for Tetrabenazine+haloperidol. Activity isshown by dose for each recorded time period. Animals were allocated intofour different treatment groups, n=5. The treatment groups consisted ofVehicle 1:1 (saline; NaCl 0.9% v/w+5.5% glukos with a few drops of HAc)the second group consisted of a single dose of Tetrabenazine (0.64mg/kg) and the third and fourth groups consisted of Haloperidol testedin two doses (0.04 and 0.12 mg/kg together with Tetrabenazine in onedose (0.64 mg/kg). All compounds were injected s.c. four minutes beforestart of locomotor activity recording at a volume of 5 ml/kg.

FIG. 15. The effect of Haloperidol on Tetrabenazine induced striataldopamine increase. Animals were allocated into four different treatmentgroups, n=5. The treatment groups consisted of Vehicle 1:1 (saline; NaCl0.9% v/w+5.5% glukos with a few drops of HAc) the second group consistedof a single dose of Tetrabenazine (0.64 mg/kg) and the third and fourthgroups consisted of Haloperidol tested in two doses (0.04 and 0.12 mg/kgtogether with Tetrabenazine in one dose (0.64 mg/kg). All compounds wereinjected s.c. four minutes before start of locomotor activity recordingat a volume of 5 ml/kg.

FIG. 16. Arc gene expression expressed as a percentage of the meancontrol group value, following treatment with Tetrabenazine+haloperidol.Expression is shown by dose and by region (striatal arc (arcS) orfrontal cortex arc (arcF)). Animals were allocated into four differenttreatment groups, n=5. The treatment groups consisted of Vehicle 1:1(saline; NaCl 0.9% v/w+5.5% glukos with a few drops of HAc) the secondgroup consisted of a single dose of Tetrabenazine (0.64 mg/kg) and thethird and fourth groups consisted of Haloperidol tested in two doses(0.04 and 0.12 mg/kg together with Tetrabenazine in one dose (0.64mg/kg). All compounds were injected s.c. four minutes before start oflocomotor activity recording at a volume of 5 ml/kg.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a combination therapy using Pridopidineand Tetrabenazine for the treatment, prevention or alleviation of amovement disorder.

The effects of Pridopidine when given in combination with Tetrabenazinesuggest, firstly, that the primary pharmacological effect ofPridopidine, i.e. dopamine D2 receptor blockade, is still present undercoadministration with Tetrabenazine. This is reflected by the additionalincrease in stratital DOPAC induced by Pridopidine in Tetrabenazinetreated rats. Given that a reduced tone at striatal D2 receptors is theproposed mechanism by which Tetrabenazine can alleviate involuntarymovements in e.g. Huntington's disease, Tourettes disorder and tardivedyskinesia, this suggests that combining Tetrabenazine with Pridopidinecould give additional clinical benefit in these disorders.

Secondly, Pridopidine reversed the behavioural inhibition caused byTetrabenazine. This behavioural inhibition is a preclinical correlate ofsome troublesome dopamine related side effects limiting the use ofTetrabenazine, especially the clear-cut motor side effects, such asparkinsonism, i.e. reduced motility, but also possibly depressed mood.It should be noted that this reversal of the behavioural inhibitioninduced by Tetrabenazine is not to be expected from a compound acting asa pure antagonist at dopamine D2 receptors, such as Pridopidine, and wasnot observed in a similar study performed with the dopamine D2antagonist Haloperidol. Rather, co-treatment with Haloperidol furtherreduced locomotor activity.

Hence, these preclinical behavioural data implies that Pridopidine mightcounteract the adverse motor and affective effects of Tetrabenazine.

The subject invention provides a method of treating a subject afflictedwith a movement disorder comprising periodically administering to thesubject an amount of Tetrabenazine or a pharmaceutically acceptable saltthereof, and an amount of Pridopidine or a pharmaceutically acceptablesalt thereof.

The subject invention also provides a method of treating a subjectafflicted with obesity, an obesity associated disorder, or acardiovascular side effect of Pridopidine comprising administering tothe subject an amount of Pridopidine or a pharmaceutically acceptablesalt thereof, and an amount of Tetrabenazine or a pharmaceuticallyacceptable salt thereof.

In an embodiment, the amounts when taken together are more effective totreat the subject than when each agent at the same amount isadministered alone.

In an embodiment, either the amount of Tetrabenazine or apharmaceutically acceptable salt thereof when taken alone, and theamount of Pridopidine or a pharmaceutically acceptable salt thereof whentaken alone, or each such amount when taken alone is not effective totreat the subject.

The subject invention also provides a method of reducing or preventingone or more side effects of periodically administering of an amount ofTetrabenazine or a pharmaceutically acceptable salt thereof to asubject, comprising periodically administering to the subject an amountof Pridopidine or a pharmaceutically acceptable salt thereof.

In an embodiment, the one or more side effects are selected fromdepression, suicidality, akathisia, restlessness, agitation,parkinsonism, sedation, somnolence, and dysphagia.

In an embodiment, the side effect is parkinsonism.

In an embodiment, the subject is afflicted with a movement disorder.

In an embodiment, the amount of Tetrabenazine or a pharmaceuticallyacceptable salt thereof is administered via oral administration.

In an embodiment, the amount of Tetrabenazine or a pharmaceuticallyacceptable salt thereof is administered daily.

In an embodiment, the amount of Tetrabenazine or a pharmaceuticallyacceptable salt thereof is administered twice daily.

In an embodiment, the amount of Tetrabenazine or a pharmaceuticallyacceptable salt thereof is administered three times daily.

In an embodiment, the amount of Tetrabenazine or a pharmaceuticallyacceptable salt thereof is 0.05 mg/kg per day to 0.20 mg/kg per day.

In an embodiment, the amount of Tetrabenazine or a pharmaceuticallyacceptable salt thereof is 5-100 mg/day.

In an embodiment, the amount of Tetrabenazine or a pharmaceuticallyacceptable salt thereof is 12.5 mg/day, 25 mg/day, 37.5 mg/day, 50mg/day, 75 mg/day, or 100 mg/day.

In an embodiment, the amount of Pridopidine or a pharmaceuticallyacceptable salt thereof is administered via oral administration.

In an embodiment, the amount of Pridopidine or a pharmaceuticallyacceptable salt thereof is administered daily.

In an embodiment, the amount of Pridopidine or a pharmaceuticallyacceptable salt thereof is administered twice daily.

In an embodiment, the amount of Pridopidine or a pharmaceuticallyacceptable salt thereof is 1.5 μmol/kg per day to 20 μmol/kg per day.

In an embodiment, the amount of Pridopidine or a pharmaceuticallyacceptable salt thereof is 10-100 mg/day.

In an embodiment, the amount of Pridopidine or a pharmaceuticallyacceptable salt thereof is 10 mg/day, 20 mg/day, 22.5 mg/day, 45 mg/day,or 90 mg/day.

In an embodiment, the movement disorder is Huntington's disease,Tourette's syndrome, or tardive dyskinesia.

In an embodiment, the amount of Tetrabenazine or a pharmaceuticallyacceptable salt thereof and the amount of Pridopidine or apharmaceutically acceptable salt thereof is effective to alleviate asymptom of the movement disorder.

In an embodiment, the symptom is chorea.

In an embodiment, the subject is receiving Tetrabenazine therapy priorto initiating administration of Pridopidine or a pharmaceuticallyacceptable salt thereof.

In an embodiment, the amount of Tetrabenazine or a pharmaceuticallyacceptable salt thereof and the amount of Pridopidine or apharmaceutically acceptable salt thereof are administeredsimultaneously.

In an embodiment, the subject is a human patient.

The subject invention also provides a package comprising:

-   a) a first pharmaceutical composition comprising an amount of    Tetrabenazine or a pharmaceutically acceptable salt thereof and a    pharmaceutically acceptable carrier;-   b) a second pharmaceutical composition comprising and amount of    Pridopidine or pharmaceutical acceptable salt thereof and a    pharmaceutically acceptable carrier; and-   c) instruction for use for the first and the second pharmaceutical    compositions together to treat a subject afflicted a movement    disorder.

In an embodiment, the package is for use in treating a subject afflictedwith a movement disorder.

In an embodiment, the movement disorder is Huntington's disease,Tourette's syndrome, or tardive dyskinesia.

The subject invention also provides Pridopidine or pharmaceuticallyacceptable salt thereof for use as an add-on therapy of or incombination with Tetrabenazine or pharmaceutical acceptable salt thereofin treating a subject afflicted with a movement disorder.

In an embodiment, the movement disorder is Huntington's disease,Tourette's syndrome, or tardive dyskinesia.

The subject invention also provides a pharmaceutical compositioncomprising an amount of Tetrabenazine or pharmaceutically acceptablesalt thereof, an amount of Pridopidine or pharmaceutical acceptable saltthereof, and at least one pharmaceutical acceptable carrier.

In an embodiment, the amount of Tetrabenazine or pharmaceuticallyacceptable salt thereof is 5-100 mg.

In an embodiment, the amount of Tetrabenazine or pharmaceuticallyacceptable salt thereof is 5 mg, 6.25 mg, 12.5 mg, 25 mg, 37.5 mg, 50mg, 75 mg, or 100 mg.

In an embodiment, the amount of Pridopidine or pharmaceutical acceptablesalt thereof is 10-100 mg.

In an embodiment, the amount of Pridopidine or pharmaceutical acceptablesalt thereof is 10 mg, 22.5 mg, 45 mg, or 90 mg.

In an embodiment, the pharmaceutical composition is for use in treatinga subject afflicted with a movement disorder.

In an embodiment, the movement disorder is Huntington's disease,Tourette's syndrome, or tardive dyskinesia.

In an embodiment, the pharmaceutical composition is for use in treating,preventing or alleviating a subject afflicted with obesity, an obesityassociated disorder, or a cardiovascular side effects of Pridopidine.

The subject invention also provides the use of:

-   a) an amount of Tetrabenazine or pharmaceutically acceptable salt    thereof; and-   b) an amount of Pridopidine or pharmaceutically acceptable salt    thereof

in the preparation of a combination for treating a subject afflictedwith a movement disorder wherein the amount of Tetrabenazine orpharmaceutically acceptable salt thereof and the amount of Pridopidineor pharmaceutically acceptable salt thereof are administeredsimultaneously or contemporaneously.

In an embodiment, the movement disorder is Huntington's disease,Tourette's syndrome, or tardive dyskinesia.

The subject invention also provides a pharmaceutical compositioncomprising an amount of Tetrabenazine or a pharmaceutically acceptablesalt thereof for use in treating a subject afflicted with a movementdisorder, in combination with an amount of Pridopidine orpharmaceutically acceptable salt thereof, by periodically administeringto the subject the pharmaceutical composition and the amount ofPridopidine or pharmaceutically acceptable salt thereof.

The subject invention also provides a pharmaceutical compositioncomprising an amount of Pridopidine or pharmaceutically acceptable saltthereof for use treating a subject afflicted with a movement disorder,in combination with an amount of Tetrabenazine or a pharmaceuticallyacceptable salt thereof, by periodically administering to the subjectthe pharmaceutical composition and the amount of Tetrabenazine or apharmaceutically acceptable salt thereof.

In an embodiment, the movement disorder is Huntington's disease,Tourette's syndrome, or tardive dyskinesia.

The subject invention also provides Tetrabenazine or a pharmaceuticallyacceptable salt thereof and Pridopidine or a pharmaceutically acceptablesalt thereof for the treatment of a subject afflicted with a movementdisorder, wherein the Tetrabenazine or a pharmaceutically acceptablesalt thereof and the Pridopidine or a pharmaceutically acceptable saltthereof are administered simultaneously, separately or sequentially.

In an embodiment, the movement disorder is Huntington's disease,Tourette's syndrome, or tardive dyskinesia.

The subject invention also provides a product containing an amount ofTetrabenazine or a pharmaceutically acceptable salt thereof and anamount of Pridopidine or a pharmaceutically acceptable salt thereof forsimultaneous, separate or sequential use in treating a subject afflictedwith a movement disorder.

In an embodiment, the movement disorder is Huntington's disease,Tourette's syndrome, or tardive dyskinesia.

The subject invention also provides a method of treating a subjectafflicted with obesity, an obesity associated disorder or acardiovascular side effect of Pridopidine comprising administering tothe subject a combination of a therapeutically effective amount ofPridopidine or a pharmaceutically acceptable salt thereof, and atherapeutically effective amount of Tetrabenazine or a pharmaceuticallyacceptable salt thereof, wherein the amounts when taken together areeffective to treat the subject.

In an embodiment, the subject is a human patient.

The subject invention also provides a combination of Pridopidine, or apharmaceutically acceptable salt thereof; and Tetrabenazine, or apharmaceutically acceptable salt thereof; for the treatment, preventionor alleviation of obesity, or an obesity associated disorder, and fortreatment, prevention or alleviation of the cardiovascular side effectsof Pridopidine, in a mammal, including a human.

In another aspect, the present invention relates to a combinationtherapy in which a pharmaceutically effective amount of Pridopidine, ora pharmaceutically acceptable salt thereof, is administered togetherwith a therapeutically effective amount of Tetrabenazine, or apharmaceutically acceptable salt thereof, for the treatment, preventionor alleviation of a movement disorder.

In a preferred embodiment the hyperkinetic movement disorder is aninvoluntary hyperkinetic movement disorder arising from Huntington'sdisease, Gilles de la Tourette's syndrome, or tardive dyskinesia, and inparticular an involuntary hyperkinetic movement disorder arising fromHuntington's disease.

Viewed from another aspect, the invention provides a combination ofPridopidine, or a pharmaceutically acceptable salt thereof, andTetrabenazine, or a pharmaceutically acceptable salt thereof, for use asa medicament.

In another aspect, the invention relates to the use of a combination of

-   (i) Pridopidine, or a pharmaceutically acceptable salt thereof; and-   (ii) Tetrabenazine, or a pharmaceutically acceptable salt thereof;

for the manufacture of a medicament for the treatment, prevention oralleviation of a movement disorder of a mammal, including a human.

In another aspect, the invention provides pharmaceutical compositionscomprising Pridopidine, or a pharmaceutically acceptable salt thereof,for use in a combination therapy together with Tetrabenazine, orpharmaceutically acceptable salt thereof, for the treatment, preventionor alleviation of a hyperkinetic movement disorder.

In another aspect the invention provides a method for the treatment,prevention or alleviation of a hyperkinetic movement disorder in aliving animal body, which method comprises the step of administering tosuch animal bodies in need thereof, a therapeutically effective amountof Pridopidine, or a pharmaceutically acceptable salt thereof; in acombination therapy with Tetrabenazine, or a pharmaceutically acceptablesalt thereof.

In another aspect the invention provides a pharmaceutical compositioncomprising a therapeutically effective amount of Pridopidine, or apharmaceutically acceptable salt thereof, and a therapeuticallyeffective amount of Tetrabenazine, or a pharmaceutically acceptable saltthereof.

In a further aspect the invention provides for a kit of parts comprisingat least two separate unit dosage forms (A) and (B), wherein (A)comprises Pridopidine, or a pharmaceutically acceptable salt thereof;and (B) comprises Tetrabenazine, or a pharmaceutically acceptable saltthereof, and optionally (C), instructions for the simultaneous,sequential or separate administration of the Pridopidine of (A) and theTetrabenazine of (B), to a patient in need thereof.

In a further aspect the invention provides an article of manufacture,comprising (A) a first pharmaceutical dosage form comprisingPridopidine, or a pharmaceutically acceptable salt thereof; and (B) asecond pharmaceutical dosage form comprising Tetrabenazine, or apharmaceutically acceptable salt thereof; wherein the article containsfirst and second pharmaceutical dosage forms.

In a further aspect the invention provides a method of treating asubject afflicted with a movement disorder comprising administering tothe subject a combination of a therapeutically effective amount ofPridopidine or a pharmaceutically acceptable salt thereof, and atherapeutically effective amount of Tetrabenazine or a pharmaceuticallyacceptable salt thereof, wherein the amounts when taken together areeffective to treat the human patient.

In an embodiment, the movement disorder is an involuntary hyperkineticmovement disorder arising from Huntington's disease, Gilles de laTourette's syndrome, or tardive dyskinesia.

In an embodiment, the movement disorder is an involuntary hyperkineticmovement disorder arising from Huntington's disease

In a further aspect the invention provides a method of treating amammal, including a human, afflicted with an obesity, or an obesityassociated disorder or of the cardiovascular side effects of Pridopidinecomprising administering to the subject a combination of atherapeutically effective amount of Pridopidine or a pharmaceuticallyacceptable salt thereof, and a therapeutically effective amount ofTetrabenazine or a pharmaceutically acceptable salt thereof, wherein theamounts when taken together are effective to treat a mammal.

In an embodiment, the therapeutically effective amount of Pridopidine orthe pharmaceutically acceptable salt thereof, and the therapeuticallyeffective amount of Tetrabenazine or the pharmaceutically acceptablesalt thereof are administered orally.

In an embodiment, the therapeutically effective amount of Pridopidine orthe pharmaceutically acceptable salt thereof, and the therapeuticallyeffective amount of Tetrabenazine or the pharmaceutically acceptablesalt thereof are administered intravenously.

In an embodiment, the therapeutically effective amount of Pridopidine orthe pharmaceutically acceptable salt thereof, and the therapeuticallyeffective amount of Tetrabenazine or the pharmaceutically acceptablesalt thereof are administered by direct penetration of the drug throughthe stratum corneum.

The Pridopidine containing medicament may be applied simultaneously withTetrabenazine, in a sequential manner, or by separate administration.Preferably Pridopidine is given at the same time as Tetrabenazine.

It is currently believed that Pridopidine may be used (co-administeredwith Tetrabenazine) in a therapeutically effective amount in the rangeof about 0.01-1000 mg API daily, more preferred in the range of about1-500 mg API daily, even more preferred in the range of about 10-200 mgAPI daily.

It is currently believed that Tetrabenazine may be used (co-administeredwith Pridopidine) in a therapeutically effective amount in the range ofabout 0.01-1000 mg API daily, more preferred in the range of about 1-500mg API daily, even more preferred in the range of about 10-200 mg APIdaily.

Pridopidine and Tetrabenazine may be co-administered by any conventionalroute. In a preferred embodiment Pridopidine and Tetrabenazine areadministered either orally, intravenously, intravascularly,intraperitoneally, sub-cutaneously, intramuscularly, inhalatively,topically, by patch, or by suppository.

In a more preferred embodiment Pridopidine and Tetrabenazine areadministered orally (p.c.).

In another more preferred embodiment Pridopidine and Tetrabenazine areadministered intravenously (i.v.).

In another embodiment Pridopidine and Tetrabenazine are administered bysubcutaneous (s.c.) injection.

Any combination of two or more of the embodiments described herein isconsidered within the scope of the present invention.

Pharmaceutically Acceptable Salts

The active compounds for use according to the invention may be providedin any form suitable for the intended administration. Suitable formsinclude pharmaceutically (i.e. physiologically) acceptable salts, andpre- or prodrug forms of the compound of the invention.

Examples of pharmaceutically acceptable addition salts include, withoutlimitation, the non-toxic inorganic and organic acid addition salts suchas the hydrochloride, the hydrobromide, the nitrate, the perchlorate,the phosphate, the sulphate, the formate, the acetate, the aconate, theascorbate, the benzenesulphonate, the benzoate, the cinnamate, thecitrate, the embonate, the enantate, the fumarate, the glutamate, theglycolate, the lactate, the maleate, the malonate, the mandelate, themethanesulphonate, the naphthalene-2-sulphonate, the phthalate, thesalicylate, the sorbate, the stearate, the succinate, the tartrate, thetoluene-p-sulphonate, and the like. Such salts may be formed byprocedures well known and described in the art.

Pharmaceutical Compositions

While the compounds for use according to the invention may beadministered in the form of the raw compound, it is preferred tointroduce the active ingredients, optionally in the form ofphysiologically acceptable salts, in a pharmaceutical compositiontogether with one or more adjuvants, excipients, carriers, buffers,diluents, and/or other customary pharmaceutical auxiliaries.

In a preferred embodiment, the invention provides pharmaceuticalcompositions comprising the active compounds or pharmaceuticallyacceptable salts or derivatives thereof, together with one or morepharmaceutically acceptable carriers therefore, and, optionally, othertherapeutic and/or prophylactic ingredients know and used in the art.The carrier(s) must be “acceptable” in the sense of being compatiblewith the other ingredients of the formulation and not harmful to therecipient thereof.

The pharmaceutical composition of the invention may be administered byany convenient route, which suits the desired therapy. Preferred routesof administration include oral administration, in particular in tablet,in capsule, in dragé, in powder, or in liquid form, and parenteraladministration, in particular cutaneous, subcutaneous, intramuscular, orintravenous injection. The pharmaceutical composition of the inventioncan be manufactured by the skilled person by use of standard methods andconventional techniques appropriate to the desired formulation. Whendesired, compositions adapted to give sustained release of the activeingredient may be employed.

Further details on techniques for formulation and administration may befound in the latest edition of Remington's Pharmaceutical Sciences(Maack Publishing Co., Easton, Pa.).

The actual dosage of each of the active ingredients depends on thenature and severity of the disease being treated, the exact mode ofadministration, form of administration and is within the discretion ofthe physician, and may be varied by titration of the dosage to theparticular circumstances of this invention to produce the desiredtherapeutic effect. However, the below dosages for the compound and theanti-obesity compound are considered suitable.

The dosage of the compound is determined as the API (ActivePharmaceutical Ingredient), i.e. calculated as the free base.

A daily dosage in the range of about 0.1-2 mg API daily, preferably ofabout 0.25-1 mg API daily, especially 0.25, 0.5 or 1.0 mg API daily, issuitable for therapeutic treatments. The daily dosage of the compoundmay be administered in one or several doses, such as two, per day. Inone embodiment, the daily dosage is administered in one dose.

The daily dosage of the anti-obesity compound is presently contemplatedto be in the range of about 0.1-500 mg of active ingredient depending onthe actual compound. More specific dosage intervals may be in the rangeof about 0.1-2 mg, about 1-10 mg, about 10-50 mg, about 25-100 mg, about50-200 mg and about 100-500 mg daily. The daily dosage of theanti-obesity compound may be administered in one or several doses, suchas two, per day. In one embodiment, the daily dosage is administered inone dose.

As used herein, “effective” as in an amount effective to achieve an endmeans the quantity of a component that is sufficient to yield anindicated therapeutic response without undue adverse side effects (suchas toxicity, irritation, or allergic response) commensurate with areasonable benefit/risk ratio when used in the manner of thisdisclosure. For example, an amount effective to treat a movementdisorder. The specific effective amount will vary with such factors asthe particular condition being treated, the physical condition of thepatient, the type of mammal being treated, the duration of thetreatment, the nature of concurrent therapy (if any), and the specificformulations employed and the structure of the compounds or itsderivatives.

As used herein, to “treat” or “treating” encompasses, e.g., inducinginhibition, regression, or stasis of the disorder and/or disease. Asused herein, “inhibition” of disease progression or disease complicationin a subject means preventing or reducing the disease progression and/ordisease complication in the subject.

As used herein, “combination” means an assemblage of reagents for use intherapy either by simultaneous or contemporaneous administration.Simultaneous administration refers to administration of an admixture(whether a true mixture, a suspension, an emulsion or other physicalcombination) of the Pridopidine and the Tetrabenazine. In this case, thecombination may be the admixture or separate containers of thePridopidine and the Tetrabenazine that are combined just prior toadministration. Contemporaneous administration refers to the separateadministration of the Pridopidine and the Tetrabenazine at the sametime, or at times sufficiently close together that a synergisticactivity or an activity that is additive or more than additive relativeto the activity of either the Pridopidine or the Tetrabenazine alone isobserved.

As used herein, “DOPAC” is 3,4-Dihydroxyphenylacetic acid.

As used herein, “LMA” is Locomotor activity.

As used herein, “TBZ” is Tetrabenazine.

Pharmaceutical Kits of Parts

According to the invention there is also provided a kit of partscomprising at least two separate unit dosage forms (A) and (B), wherein

-   (A) comprises Pridopidine, or a pharmaceutically acceptable salt    thereof; and-   (B) comprises Tetrabenazine, or a pharmaceutically acceptable salt    thereof; and optionally-   (C) instructions for the simultaneous, sequential or separate    administration of the Pridopidine of (A) and the Tetrabenazine of    (B), to a patient in need thereof.

Pridopidine for use according to the invention and Tetrabenazine for useaccording to the invention may preferably be provided in a form that issuitable for administration in conjunction with the other. This isintended to include instances where one or the other of two formulationsmay be administered (optionally repeatedly) prior to, after, and/or atthe same time as administration with the other component.

Also, Pridopidine for use according to the invention and Tetrabenazinefor use according to the invention may be administered in a combinedform, or separately or separately and sequentially, wherein thesequential administration is close in time or remote in time. This mayin particular include that two formulations are administered (optionallyrepeatedly) sufficiently closely in time for there to be a beneficialeffect for the patient, that is greater over the course of the treatmentof the relevant condition than if either of the two formulations areadministered (optionally repeatedly) alone, in the absence of the otherformulation, over the same course of treatment. Determination of whethera combination provides a greater beneficial effect in respect of, andover the course of treatment of, a particular condition, will dependupon the condition to be treated or prevented, but may be achievedroutinely by the person skilled in the art.

When used in this context, the terms “administered simultaneously” and“administered at the same time as” include that individual doses ofPridopidine and Tetrabenazine are administered within 48 hours, e.g. 24hours, of each other.

Bringing the two components into association with each other, includesthat components (A) and (B) may be provided as separate formulations(i.e. independently of one another), which are subsequently broughttogether for use in conjunction with each other in combination therapy;or packaged and presented together as separate components of a“combination pack” for use in conjunction with each other in combinationtherapy.

According to the invention there is also provided an article ofmanufacture, comprising (A) a first pharmaceutical dosage formcomprising Pridopidine, or a pharmaceutically acceptable salt thereof;and (B) a second pharmaceutical dosage form comprising Tetrabenazine, ora pharmaceutically acceptable salt thereof; wherein the article containsfirst and second pharmaceutical dosage forms.

Methods of Therapy

In another aspect the invention provides methods of treatment,prevention or alleviation of a hyperkinetic movement disorder in aliving animal body, including a human, which method comprises the stepof administering to such a living animal body in need thereof, atherapeutically effective amount of Pridopidine, or a pharmaceuticallyacceptable salt thereof; in a combination therapy with Tetrabenazine, ora pharmaceutically acceptable salt thereof.

The hyperkinetic movement disorder may in particular be an involuntarymovement disorder arising from Huntington's disease, Gilles de laTourette's syndrome, or tardive dyskinesia.

In a preferred embodiment, the hyperkinetic movement disorder is aninvoluntary movement disorder arising from Huntington's disease.

Introduction to the Examples

Motor function is controlled by a complex circuitry connecting thecerebral cortex with subcortical structures including the basal gangliaand the thalamus. One major pathway within this circuitry is the socalled “indirect pathway” forming a closed feed-back loop connecting thecortex, the striatum, and the thalamus via a population of striatalGABA-ergic, medium spiny neurons expressing dopamine D2 type receptors.This pathway functions as a negative regulator of movements, and isimportant for the suppression of excessive movements. Dopamine modulatesthe indirect pathway by inhibitory dopamine D2 receptors in such a waythat increased dopamine tone at these receptors leads to a reducedactivity of the indirect pathway, and therefore a reduced ability tosuppress movements. On the other hand, a diminished dopamine tone leadsto increased activity of the indirect pathway associated with strongersuppression of movements.

Another important cortico-striato-thalamic pathway involved in motorcontrol is the so called “direct pathway”, forming a closed, positivefeed-back loop via striatal GABA-ergic, medium spiny neurons expressingdopamine DI type receptors. The direct pathway is a positive modulatorof motor function, involved in the selection and enabling of voluntarymovements. Dopamine, acting at D1 type receptors, stimulates thestriatal GABA-ergic neurons in the direct pathway, thereby enhancingmovements. Conversely, a reduction in dopamine tone at these D1receptors leads to a reduced ability to perform voluntary movements.

The general reduction in dopamine transmission resulting from treatmentwith Tetrabenazine also reduces other dopamine dependent functions. Inparticular, the dopamine tone at the direct pathway, with striatalneurons expressing dopamine D1 receptors, is also reduced, leading to aweakening of the direct pathway and therefore to a reduced capacity toperform voluntary movements. Furthermore, the dopamine depletion inducedby Tetrabenazine is likely to impair dopamine dependent motivation andreward, which is hypothesised to underlie the pro-depressant adverseeffects of Tetrabenazine.

Given that Pridopidine is a pure antagonist at dopamine D2 receptors,with no agonist activity, it was expected that a therapeutic combinationof Pridopidine and Tetrabenazine would lead to further reduced tone atdopamine D2 receptors, and therefore to a further reduction in overalllocomotor activity, compared to treatment with Tetrabenazine only.

EXAMPLES

The invention is further illustrated with reference to the followingexamples, which are not intended to be in any way limiting to the scopeof the invention as claimed.

The examples below explore the interaction between Pridopidine andTetrabenazine with respect to locomotor activity. Striatal levels ofdopamine and DOPAC were also determined. Tetrabenazine reduces tissuelevels of dopamine as a direct consequence of the inhibition of VMAT.Both compounds increase striatal DOPAC levels in a dose-dependent mannerin vivo, reflecting decreased tone at the dopamine D2 receptor (Ponten2010; Reches, 1983). Furthermore, the effect on expression of theimmediate-early gene Arc (activity-regulated cytoskeleton-associatedprotein/activity-regulated gene 3.1) was measured in the frontal cortexand striatum. Arc gene expression is a biomarker reflecting synapticactivity (Steward, 2001; Kawashima 2009). Interaction experiments withTetrabenazine and the dopamine D2 antagonist haloperidol were alsoperformed in order to compare the effects of Pridopidine with those of aclassical dopamine D2 receptor antagonist

1) Effect of Tetrabenazine on Locomotor Activity, Striatal DOPAC, andArc

Tetrabenazine was given sc at 0.37, 0.64 and 1.1 mg/kg. LMA was recordedfor 60 minutes after dosing. Thereafter rats were sacrificed and brainswere collected. Analyses of brain tissues included DOPAC in thestriatum, and Arc mRNA in the frontal cortex and striatum.

Tetrabenazine reduced locomotor activity. (FIG. 1). Tetrabenazine dosedependently inhibited spontaneous locomotor activity. When the full hourof recording was considered, the 1.1 mg/kg Tetrabenazine dose groupdisplayed a significant reduction to 40% of the vehicle control groupmean (P<0.01). During the initial 15 min significant reductions (P<0.05)were seen both for the 1.1 and 0.37 mg/kg Tetrabenazine dose groups,whereas for the period 15-60 minutes post dosing significant effects(P_(<)0.05) were observed at 0.64 and 1.1 mg/kg. The reduction inlocomotor activity reflects the decreased dopamine transmission causedby inhibition of VMAT2.

Tetrabenazine dose dependently increases striatal DOPAC, withstatistically significant effects at all doses tested. The increase inDOPAC is a neuronal marker of reduced tone at dopamine D2 receptors, dueto the decreased dopamine transmission in rats treated withTetrabenazine. See Table 1 and FIG. 1-2.

Arc in Striatum and Cortex: Tetrabenazine increased striatal Arc andreduced frontal cortex Arc. Tetrabenazine dose dependently increased ArcmRNA in the striatum, reaching 147% of the vehicle control group mean(P<0.01) at the highest dose tested (1.1 mg/kg). In the frontal cortex,a significant reduction of Arc mRNA down to 66% of the vehicle controlgroup mean was observed at Tetrabenazine dose of 1.1 mg/kg (P<0.05). AtTetrabenazine dose of 0.64 mg/kg, there was a trend towards a reductionin frontal cortex mRNA (83% of control group mean, p=0.14). See FIG. 3.The Arc increase in the striatum is most likely due to reduced tone atdopamine D2 receptors. The Arc decrease in the frontal cortex is likelyto be related to decreased dopamine transmission in the cortex leadingto a reduced tone at dopamine D1 receptors.

2) Effect of Pridopidine on Locomotor Activity, Striatal DOPAC, and Arc

Pridopidine was given sc at 11, 33 and 100 μmol/kg. Pridopidinedisplayed no inhibitory effect on spontaneous locomotor activity. Aslight increase in locomotor activity was observed at the mid dose, 33μmol/kg, over the full 60 minute recording period. See FIG. 4. When thefull hour of recording was examined, a significant increase in locomotoractivity to 138% of the vehicle control group mean was observed for the33 μmol/kg Pridopidine dose group (P<0.05). During the initial 15 min asignificant increase (P<0.05) was seen for the 11 μmol/kg Pridopidinedose group, whereas for the period 15-60 minutes post dosing nosignificant effects were observed.

Pridopidine dose dependently increases striatal DOPAC, withstatistically significant effects at all doses tested. The increase inDOPAC is a neuronal marker of reduced tone at dopamine D2 receptors, dueto dopamine D2 receptor antagonism exerted by Pridopidine. See FIG. 5and Table 1.

Pridopidine dose-dependently increased striatal and cortical arc geneexpression, reaching statistical significance at the highest dosestested. Pridopidine increased Arc mRNA levels in the frontal cortex in adose-dependent manner, up to 149% (p<0.01) and 222% (p<0.001) of thevehicle control group mean at doses of 33 μmol/kg and 100 μmol/kg,respectively (FIG. 6). Pridopidine increased Arc mRNA levels in thestriatum in a dose-dependent manner. Compared with the relevant controlgroup means, levels reached 168% and 253% (p<0.01 for both doses atPridopidine 33 μmol/kg and 100 μmol/kg, respectively). (FIG. 6). The Arcincrease in the striatum is most likely due to reduced tone at dopamineD2 receptors. The Arc increase in the frontal cortex is likely to berelated to increased dopamine transmission in the cortex leading to anincreased tone at dopamine D1 receptors.

3) Effect of Haloperidol on Locomotor Activity, Striatal DOPAC, and Arc

Haloperidol was given sc at 0.12, 0.37 and 1.1 mg/kg (See FIG. 7). In anadditional experiment assessing effects at lower doses, 0.04, 0.12. 0.37and 1.1 mg was given (See FIG. 302). Haloperidol displayed adose-dependent inhibitory effect on spontaneous locomotor activity.Statistically significant effects were observed at 0.12 mg/kg and higherdoses, but not at the lowest dose tested, 0.04 mg/kg.

More specifically, when the full hour of recording was considered, the0.37 and 1.1mg/kg haloperidol dose groups displayed significantreductions to about 35% of the vehicle control group mean (P<0.05).During the initial 15 min, significant reductions (P<0.05) were seenboth for the 0.37 and 1.1 mg/kg haloperidol dose groups, whereas for theperiod 15-60 minutes post dosing a significant effect (P<0.05) wasobserved for the 1.1 mg/kg dose group only.

Haloperidol dose dependently increases striatal DOPAC, withstatistically significant effects at all doses tested. The increase inDOPAC is a neuronal marker of reduced tone at dopamine D2 receptors, dueto dopamine D2 receptor antagonism. See Table 1 and FIG. 9.

Haloperidol dose dependently increased Arc mRNA in the striatum,reaching 262% (P<0.01), 331% (P<0.001), 409% (P<0.01), respectively, ofthe vehicle control group mean at the 0.12 mg/kg, 0.37 mg/kg and 1.1mg/kg doses. The Arc increase in the striatum is most likely due toreduced tone at dopamine D2 receptors. There was no significant effectof Haloperidol on cortical Arc gene expression. See FIG. 10.

TABLE 1 Effects on striatal DOPAC in drug-naive andTetrabenazine-treated rats Dose- Dose- Interaction Interaction responsein response in with with naive rats naive rats TetrabenazineTetrabenazine Test Dose DOPAC DA DOPAC DA compound group striatumstriatum striatum striatum Tetrabenazine 100 ± 06 100 ± 6 — — 0.37 mg/kg144 ± 8**  48 ± 2*** — — 0.64 mg/kg 208 ± 14***  33 ± 3*** — —  1.1mg/kg 263 ± 19***  20 ± 2*** — — Pridopidine C 100 ± 5 100 ± 3  53 ±1^(††) 299 ± 13^(†††) TC — — 100 ± 11 100 ± 10   11 μmol/kg 117 ± 5* 104± 3 — —   33 μmol/kg 178 ± 7*** 101 ± 3 123 ± 8  91 ± 11  100 μmol/kg236 ± 17***  73 ± 4** 155 ± 4^(††)  98 ± 8 Haloperidol C 100 ± 22 100 ±5  65 ± 3^(†††) 202 ± 9^(†††) TC — — 100 ± 3 100 ± 8 0.04 mg/kg 171 ± 35 95 ± 5 187 ± 6^(†††)  79 ± 3^(†) 0.12 mg/kg 276 ± 8***  78 ± 3** 218 ±12^(†††)  87 ± 10 0.37 mg/kg 254 ± 17**  79 ± 5* — —  1.1 mg/kg 292 ±10***  81 ± 2* — — Data are shown as mean ± SEM DOPAC levels, expressedas percentages of control group mean. C, vehicle control group; DOPAC,3,4-dihydroxyphenylacetic acid; TC, Tetrabenazine control group *p <0.05; **p < 0.01***; p < 0.001 vs. vehicle control group; ^(†)p < 0.05;^(††)p < 0.01; ^(†††)p < 0.001 vs. Tetrabenazine control group.

In summary, while all three antidopaminergic compounds producedincreased striatal DOPAC, and increased striatal arc gene expression,both effects most likely related to decreased tone at dopamine D2receptors, Pridopidine was unique in that it did not inhibit locomotoractivity. Another feature differentiating Pridopidine from Haloperidolor Tetrabenazine, is that it increased cortical Arc gene expression.

Combination Experiments

To test the effect of dopamine D2 antagonist when administered topartially dopamine depleted animals, Haloperidol and Pridopidine werecombined with Tetrabenazine at a dose that produced submaximal butsignificant effects on striatal dopac and locomotor activity.

4) Effect of Pridopidine on Tetrabenazine Induced Locomotor ActivityReduction, Striatal Dopamine Increase, and Arc

In the interaction experiment with Pridopidine and Tetrabenazine,Pridopidine was given at 33 and 100 μmol/kg, combined with Tetrabenazineat 0.64 mg/kg. See FIG. 11. The locomotor recordings demonstrated thatPridopidine reversed the behavioural inhibition induced byTetrabenazine. However, the effects on striatal DOPAC were additive,i.e. coadministration of Pridopidine further increased striatal DOPAC.

For the locomotor inhibition, there was a significant decrease in theTetrabenazine control group vs. vehicle treated controls for the fullhour of recording (P<0.001), as well for both the 0-15 min period(P<0.01) and the 15-60 min period (P<0.01). Considering the full hour ofrecording, Pridopidine reversed the locomotor inhibition induced byTetrabenazine at both the 33 and the 100 μmol/kg dose groups, reaching135% (P<0.05) and 137% (P<0.01), respectively of

Tetrabenazine control mean. During the 0-15 min as well as for the 15-60min periods this reversing effect reached significance for thePridopidine 100 μmol/kg dose group. This implies that the tone atstriatal D2 receptors is further reduced when adding Pridopidine tomonoamine depleted animals. See FIG. 11.

In the interaction experiment where Tetrabenazine 0.64 mg/kg wascombined with either Pridopidine 33 μmol/kg or 100 μmol/kg,Tetrabenazine induced a significant increase in striatal DOPAC levelswas seen compared with the vehicle-treated control group (p<0.01; Table1). Pridopidine further increased DOPAC levels in striatum, reaching155% of the Tetrabenazine control group mean at the 100 μmol/kg dose(p<0.01). See Table 1 and FIG. 12.

Likewise, striatal Arc expression was further increased by addingPridopidine. In contrast, the Arc decrease induced by Tetrabenazine wascounteracted by Pridopidine.

Pridopidine reversed the decrease in frontal cortex Arc induced byTetrabenazine as shown in FIG. 13. More specifically, Tetrabenazine hadno significant effect on striatal Arc mRNA at the 0.64 mg/kg dose usedin the interaction experiment. Pridopidine, when coadministered withTetrabenazine, dose dependently increased striatal Arc, reaching 144%(P<0.05) and 207% (P<0.01), respectively, of the Tetrabenazine controlgroup mean at the 33 μmol/kg, and the 100 μmol/kg doses of Pridopidine.

Tetrabenazine induced a significant decrease (P<0.05) in frontal cortexArc mRNA, which is in accordance with the trend towards a decrease offrontal cortex Arc mRNA at the 0.64 mg/kg dose observed in the doseresponse experiment with Tetrabenazine (FIG. 3). Pridopidine dosedependently reversed the decrease in frontal cortex Arc mRNA induced byTetrabenazine. At 33 μmol/kg and 100 μmol/kg of Pridopidine, Arc mRNAwas increased to 125% (P<0.05) and 193% (P<0.05), respectively, of theTetrabenazine control group mean

5) Effect of Haloperidol on Tetrabenazine Induced Locomotor ActivityReduction, Striatal Dopamine Increase, and Arc

In the interaction experiment with Haloperidol and Tetrabenazine,Haloperidol was given at 0.04 and 0.12 mg/kg, combined withTetrabenazine at 0.64 mg/kg.

The locomotor recordings showed that Haloperidol further reducedlocomotor activity in animals treated with Tetrabenazine. Morespecifically, the locomotor recording over the full hour demonstratedthat haloperidol significantly (P<0.01) reduced locomotor activity inrats treated with Tetrabenazine both at the 0.04 and 0.12 mg/kg doses,down to 51% and 41% of Tetrabenazine control group mean, respectively.For the first 15 min of recording this reducing effect was significantat both the 0.04 mg/kg (P<0.01) and the 0.12 mg/kg (P<0.05) doses,whereas for the 15-60 min period the reduction was significant for the0.12 mg/kg dose only (P<0.05). See FIG. 14.

The effects on striatal DOPAC were additive, i.e. coadministration ofHaloperidol with Tetrabenazine caused additional increases in striatalDOPAC. In the interaction experiment where Tetrabenazine 0.64 mg/kg wascombined with haloperidol 0.04 mg/kg or 0.12 mg/kg, Tetrabenazineinduced a significant increase in striatal DOPAC levels compared withthe vehicle-treated control group (p<0.001; Table 1). Haloperidolfurther increased DOPAC levels in striatum, reaching 187% and 218% ofthe Tetrabenazine control group mean at the 0.04 mg/kg and 0.12 mg/kgdoses, respectively (p<0.001 for both doses). See Table 1 and FIG. 15.There was no significant effect of Haloperidol on cortical Arc geneexpression in rats co-treated with Tetrabenazine. Haloperidol furtherincreases striatal Arc in Tetrabenazine treated animals (FIG. 16).Tetrabenazine had no significant effect on striatal Arc mRNA at the 0.64mg/kg dose used in the interaction experiment. Haloperidol, whencoadministered with Tetrabenazine, dose dependently increased striatalArc, reaching 272% (P<0.001) and 400% (P<0.001), respectively, of theTetrabenazine control group mean at the 0.04 mg/kg, and the 0.12 mg/kgdoses of haloperidol.

Tetrabenazine tended to decrease frontal cortex Arc mRNA (P=0.08), whichis in accordance with the trend towards a decrease of frontal cortex ArcmRNA at the 0.64 mg/kg dose observed in the dose response experimentwith Tetrabenazine (FIG. 3), and the significant decrease observed inthe interaction experiment with Pridopidine and Tetrabenazine (FIG. 13).There was no significant effect of haloperidol on frontal cortex ArcmRNA in Tetrabenazine treated animals.

Test Methods

The following tests are used for evaluation of the compounds for useaccording to the invention.

Animals

Male Sprague-Dawley rats from B&K Scanbur (Sollentuna, Sweden) (IBBS58),Charles River (Köln, Germany) (KR104, BS31) or Taconic (Ejby, Denmark)(BS85, BS81, KR219, TA284) were used. Rats weighed 160-180 g at the timeof arrival. Rats weighed 220-260 g at the time of the locomotor andtissue neurochemistry studies. Animals were housed five animals per cagewith lights on between 06:00 and 18:00. All experiments were carried outin accordance with Swedish animal protection legislation and with theapproval of the local Animal Ethics Committee in Gothenburg.

Dosing

IBBS58: Animals were allocated into four different treatment groups,n=5. The treatment groups consisted of Vehicle (saline; NaCl 0.9% v/w)and ACR16 tested at three doses (11; 33 and 100 μmol/kg).

BS31: Animals were allocated into four different treatment groups, n=5.The treatment groups consisted of Vehicle (Glucose 5.5% v/w) andHaloperidol tested at three doses (0.12; 0.37 and 1.1 μmol/kg).

KR104: Animals were allocated into five different treatment groups, n=4.The treatment groups consisted of Vehicle (Glucose 5.5% v/w) andHaloperidol tested at four doses (0.04; 0.12; 0.37 and 1.1 μmol/kg).

KR219: Animals were allocated into four different treatment groups, n=5.The treatment groups consisted of Vehicle (Glucose 5.5% v/w) andTetrabenazine tested at three doses (0.37; 0.64 and 1.1 μmol/kg).

BS81: Animals were allocated into four different treatment groups, n=5.The treatment groups consisted of Vehicle 1:1 (saline; NaCl 0.9%v/w+5.5% glukos with a few drops of HAc) the second group consisted of asingle dose of Tetrabenazine (0.64 mg/kg) and the third and fourthgroups consisted of NS30016 tested in two doses (33 and 100 μmol/kgtogether with Tetrabenazine in one dose (0.64 mg/kg).

TA284: Animals were allocated into four different treatment groups,n=10. The treatment groups consisted of Vehicle 1:1 (saline; NaCl 0.9%v/w+5.5% glukos with a few drops of HAc) the second group consisted of asingle dose of Tetrabenazine (0.64 mg/kg) and the third and fourthgroups consisted of NS30016 tested in two doses (33 and 100 μmol/kgtogether with Tetrabenazine in one dose (0.64 mg/kg). No brain tissuewas collected from this experiment.

BS85: Animals were allocated into four different treatment groups, n=5.The treatment groups consisted of Vehicle 1:1 (saline; NaCl 0.9%v/w+5.5% glukos with a few drops of HAc) the second group consisted of asingle dose of Tetrabenazine (0.64 mg/kg) and the third and fourthgroups consisted of Haloperidol tested in two doses (0.04 and 0.12 mg/kgtogether with Tetrabenazine in one dose (0.64 mg/kg).

All compounds were injected s.c. four minutes before start of locomotoractivity recording at a volume of 5 ml/kg.

In Vivo Test: Behaviour

Behavioural activity is measured using eight Digiscan activity monitors(RXYZM (16) TAO, Omnitech Electronics, Columbus, Ohio, USA), connectedto an Omnitech Digiscan analyzer and an Apple Macintosh computerequipped with a digital interface board (NB DIO-24, NationalInstruments, USA). Each activity monitor consists of a quadratic metalframe equipped with photobeam sensors. During measurements ofbehavioural activity, a rat is put in a transparent acrylic cage withmatted black floor (W×L×H, 41×41×30 cm) which in turn is placed in theactivity monitor. Each activity monitor is equipped with three rows ofinfrared photobeam sensors, each row consisting of 16 sensors. Two rowsare placed along the front and the side of the floor of the cage, at a90 degree angle, and the third row is placed 10 cm above the floor tomeasure vertical activity. Photobeam sensors are spaced 2.5 cm apart.Each activity monitor is fitted in an identical sound and lightattenuating box (W×L×H—55×55×45) containing a weak house light and afan.

The computer software is written using object oriented programming(LabVIEW™, National instruments, Austin, Tex., USA).

Behavioural data from each activity monitor, representing the position(horizontal center of gravity and vertical activity) of the animal ateach time, are recorded at a sampling frequency of 25 Hz and collectedusing a custom written LABView™ application. The data from eachrecording session are stored and analyzed with respect to distancetravelled. Each behavioural recording session lasts 60 min, startingapproximately 4 min after the injection of test compound. The resultsare presented as counts/60 minutes, counts/45 minutes or counts/15minutes, in arbitrary length units. Statistical comparisons are carriedout using Student's t-test against the control group.

In Vivo Test: Neurochemistry

Immediately after the behavioural activity sessions, the rats aredecapitated and their brains rapidly taken out and put on an ice-coldpetri-dish.

Brains were dissected into striatum, limbic region (containing thenucleus accumbens—both core and shell, amygdala, most parts of theolfactory tubercle and ventral pallidum), frontal cortex andhippocampus. Tissue samples were immediately frozen and stored at −80°C. until it was homogenized with perchloric acid (PCA) (0.1M),ethylene-diamine-tetraacetic acid (EDTA) (5,37 mM), glutathione (GSH)(0.65 mM) and alpha-methyl-dopamine (0.25 μM) as internal standard. Adigital sonifier (Branson Digital Sonifier 250-D) was used to homogenisetissue from the striatum and limbic region. Cortex tissue washomogenised using an Ultra Turrax T25 homogeniser. All samples werecentrifuged at 10.000 rpm for 10 minutes at +4° C. Cortex tissue wasfiltered in Munktell filter paper 5.5 cm quality 1F. Tissue eluates wereanalysed with respect to tissue concentrations (ng/g tissue) of themonoamine transmitter substances (Norepinephrine (NA), dopamine (DA),5-hydroxytryptamine (5-HT)) as well as their amine metabolites(normetanephrine (NM), 3-methoxytyramine (3-MT)) and acid metabolites(3,4-dihydroxyphenylalanine (DOPAC), 5-hydrocyindoleacetic acid(5-HIAA), homovanillic acid (HVA)) by HPLC separations andelectrochemical detection (HPLC/EC). Stock standards (DA, NA, 5-HT,3-MT, DOPAC, HVA, HIAA, 500 μg/ml) and internal standard (AMDA 500μg/ml) are prepared once every three months. 5-HT and 5HIAA aredissolved in milliQ water. DA, NA, DOPAC, NM, 3-MT and HVA are dissolvedin 0.01 M HCl. 5-HT, 5-HIAA, NM and HVA are kept in fridge; DA, DOPAC,NA and 3-MT are kept in freezer. Standard solution for analysescontaining standards diluted in homogenising solution to a concentrationof 0.05 μg/ml is prepared daily.

The analytical method is based on two chromatographic separationsdedicated for amines or acids. Two chromatographic systems share acommon auto injector with a 10-port valve and two sample loops forsimultaneous injection on the two systems. Both systems are equippedwith a reverse phase column (Luna C18(2), dp 3 μm, 50×2 mm i.d.,Phenomenex) and electrochemical detection is accomplished at twopotentials on glassy carbon electrodes (MF-1000, Bioanalytical Systems,Inc.). The column effluent is passed via a T-connection to the detectioncell or to a waste outlet. This is accomplished by two solenoid valves,which block either the waste or detector outlet. By preventing thechromatographic front from reaching the detector, better detectionconditions are achieved. The aqueous mobile phase (0.4 ml/min) for theacid system contains citric acid 14 mM, sodium citrate 10 mM, MeOH 15%(v/v) and EDTA 0.1 mM. Detection potentials relative to Ag/AgClreference are 0.45 and 0.60V. The aqueous ion pairing mobile phase (0.5ml/min) for the amine system contains citric acid 5 mM, sodium citrate10 mM, MeOH 9%(v/v), MeCN 10.5% v/v), decane sulfonic acid 0.45 mM, andEDTA 0.1 mM. Detection potentials relative to Ag/AgCl reference are 0.45and 0.65V.

PCR

The following methods were used for the data shown in FIG. 3, FIG. 13,and FIG. 16:

Total RNA is prepared by the guanidin isothiocyanate method(Chomczynski, 1987). RNA pellets are solved in MQ water and stored at−80° C. The sample concentration is determined spectrophotometrically bya NanoDrop ND-1000. A quality indicator number and an integrity numberof r-RNA are measured with an Experion (Bio-Rad) on random samples.

A two-step reversed transcription is performed by using a SuperScriptIII kit (Invitrogen). 1 μg of total RNA is reversed transcribed with 5μl 2×RT Reaction Mix, 1 μl RT Enzyme Mix, volume adjusted to 10 μl withDEPC-treated water. 1 U of E. coli RNase H is added. cDNA is diluted 40times and stored at −20° C.

Three sequences (one gene of interest and two reference genes) areamplified together in a triplex PCR-reaction. For real-time PCRmeasurements: 5 μl of the cDNA reaction is amplified in a 20 μl reactionmixture containing 10 μl Quanta buffer, 3.5 μl MQ, 0.15 μM of eachprimer and 0.1 μM of each probe. Real-time PCR is measured on CFX96(Biorad) using the following settings for all genes: 3 minpre-incubation at 95 degrees C. followed by 40 cycles of denaturation at95 degrees C. for 15 s, annealing and elongation at 60 degrees C. for 1minute.

Reference genes are HPRT and cyclophilin.

The primer and probe sequences are as follows for measuring of arc:

Activity-regulated gene (Arc) (Accession Number U19866) Sense:5′-GGA GTT CAA GAA GGA GTT TC-3′ Antisense:5′-CCA CAT ACA GTG TCT GGT A-3′ Probe: CCG CTT ACG CCA GAG GAA CT Dye:5′FAM Quencher: 3′BHQ1 Product size: 149Hypoxantine phosphoribosyl transferase (HPRT)(Accession Number AF001282) Sense: 5′-AGG GAT TTG AAT CAT GTT TG-3′Antisense: 5′-CTG CTA GTT CTT TAC TGG C-3′ Probe:TGT AGA TTC AAC TTG CCG CTG TC Dye: 5′HEX Quencher: 3′BHQ1 Product size:121 Cyclophilin A (Accession Number M19533) Sense:5′-CTG GAC CAA ACA CAA ATG-3′ Antisense: 5′-ATG CCT TCT TTC ACC TTC-3′Probe: TTG CCA TCC AGC CAC TCA GT Dye: 5′Texas red Quencher: 3′BHQ2Product size: 100

Correct PCR products are confirmed by agarose gel electroforesis (2%)PCR products are purified with PCR purification kit from Qiagen(Valencia, Calif., USA). All genes are sequenced at MWG, Germany. Theamounts of gene of interests are normalised with the two reference genesHPRT and cyclophilin A.

For the data shown in FIG. 6, the reverse transcription and PCR wereperformed as follows:

Reversed transcription is performed by using a ThermoScript kit(Invitrogen). 1 μg of total RNA is reverse transcribed with 25 pmololigo (dT), 62.5 ng random hexamers, 7.5 U Thermoscript RT, 10 URNaseOut, 2 μl 5×cDNA Synthesis buffer, 1 mM dNTP, 0.05 M DTT, adjustvolume to 10 μl with DEPC-treated water. Then cDNA is diluted 40 timesand stored at −20° C.

For real-time singleplex PCR measurements: 0.7 μl of the cDNA reactionis amplified in a 25 μl reaction mixture containing 1× per buffer, 0.2mM dNTP, 3.7 mM MgCl2, 0.15 mM SYBR green, 0.4 μM of primer and 1 U Taqpolymerase. Real-time PCR is measured on Icycler (Biorad) using thefollowing settings for all genes: 60 s pre-incubation at 95° C. followedby 40 cycles of denaturation at 95° C. for 20 s, annealing at 56° C. for20 s, elongation at 72° C. for 30 s.

Analysis of Arc mRNA: Dose-Response and Interaction Studies forTetrabenazine, Pridopidine, and Haloperidol

Total RNA was prepared by the guanidine isothiocyanate method (Schaefer1984). RNA pellets were dissolved in ultrapure water and stored at −80°C. RNA concentration was determined spectrophotometrically using aNanoDrop ND-1000 (Thermo Scientific, Waltham, Mass., USA). A qualityindicator number and an integrity number of ribosomal RNA weredetermined for random samples using an Experion electrophoresis system(Bio-Rad Laboratories, Hercules, Calif., USA). Reverse transcription wasperformed using a SuperScript III kit or a ThermoScript kit (both fromLife Technologies Europe BV, Stockholm, Sweden). For Tetrabenazinedose-response and interaction studies, 1 μg RNA was reverse-transcribedwith 5 μl 2×RT Reaction Mix and 1 μl RT Enzyme Mix (SuperScript IIIkit); for studies with Pridopidine and haloperidol, 1 μg RNA wasreverse-transcribed using a ThermoScript kit with 25 pmol oligo(dT),62.5 ng random hexamers, 7.5 U ThermoScript reverse transcriptase, 10 URNaseOut, 2 μl 5×cDNA Synthesis Buffer, 1 mM dNTPs and 0.05 Mdithiothreitol. In all studies, cDNA volume was adjusted to 10 μl withdiethylpyrocarbonate-treated water. Escherichia coli RNase H (1 U) wasadded, then cDNA was diluted 40 times and stored at −20° C.

cDNA of Arc and two reference genes, hypoxanthine-guaninephosphoribosyltransferase (HPRT) and cyclophilin A, was amplified byreal-time PCR in either a triplex reaction (Tetrabenazine studies) orthree singleplex reactions (studies with Pridopidine and haloperidol).For the triplex real-time PCR, 5 μl cDNA was amplified in a 20 μlreaction mixture containing 10 μl Quanta buffer (Quanta BioSciencesInc., Gaithersburg, Md., USA), 3.5 μl ultrapure water, 0.15 μM of eachprimer and 0.1 μM of each probe (the primer and probe sequences used aredetailed in Table 3). Products of the triplex real-time PCR weredetected on a CFX96 system (Bio-Rad Laboratories, Hercules, Calif., USA)using the following settings for all genes: 3 minutes pre-incubation at95° C., followed by 40 cycles of denaturation at 95° C. for 15 seconds,and annealing and elongation at 60° C. for 1 minute. For singleplexreal-time PCR measurements, 0.7 μl cDNA was amplified in a 25 μlreaction mixture containing 1×PCR buffer, 0.2 mM dNTPs, 3.7 mM MgCl₂,0.15 mM SYBR Green, 0.4 μM of primer (Table 2) and 1 U Tag polymerase.An Icycler detection system (Bio-Rad Laboratories, Hercules, Calif.,USA) was used, with the following settings for all genes: 60 secondspre-incubation at 95° C., followed by 40 cycles of denaturation at 95°C. for 20 seconds, annealing at 56° C. for 20 seconds, elongation at 72°C. for 30 seconds. Correctly sized PCR products were confirmed byelectrophoresis in agarose gel (2%); the products were then purifiedwith a PCR purification kit from Qiagen (Valencia, Calif., USA). Allgenes were sequenced at MWG Biotech (Ebersberg, Germany). The quantityof Arc mRNA was normalized to those of the two reference genes by astandard curve constructed for every gene using six serial four-folddilutions of purified PCR products.

Primers:

Hypoxantine phosphoribosyl transferase (HPRT)(Accession Number AF001282) Sense: 5′-GGC CAG ACT TGT TGG ATT TG-3′Antisense: 5′-CCG CTG TCT TTT AGG CTT TG-3′Cyclophilin A (Accession Number M19533) Sense:5′-GTC TCT TTT CGC CGC TTG CT-3′ Antisense:5′-TCT GCT GTC TTT GGA ACT TTG TCT G-3′Activity-regulated gene (Arc) (Accession Number U19866) Sense:5′-GTC CCA GAT CCA GAA CCA CA-3′ Antisense:5′-CCT CCT CAG CGT CCA CAT AC-3′

Initial DNA amounts are quantified by a standard curve constructed forevery gene using 6 serial 4-fold dilutions of purified PCR products.

For the data shown in FIG. 10, the same methods were applied as for thedata in FIG. 6, except that the PCR was run on a MyIQ thermal cycler(Biorad).

Discussion of Examples

It was demonstrated that Pridopidine reversed the behavioural inhibitioninduced by Tetrabenazine. This effect was not shared by haloperidol,which decreased locomotor activity in Tetrabenazine treated animals. Theinteraction experiments further showed that both Pridopidine andhaloperidol retained their characteristic neurochemical effects, ieincreases in striatal DOPAC, when co-administered with Tetrabenazine.Likewise, the accompanying increases in striatal arc mRNA levels inducedby Pridopidine and haloperidol were maintained in the interactionexperiments with Tetrabenazine.

In addition to locomotor depression and increased striatal DOPAC levels,Tetrabenazine produced a dose-dependent decrease in striatal dopaminelevels, which was not affected by co-administration of Pridopidine orhaloperidol. Moreover, Tetrabenazine produced a dose-dependent increasein frontal cortex Arc mRNA levels. This effect was counteracted in adose-dependent manner by Pridopidine, but not by haloperidol.

Pridopidine counteracted behavioural depression induced byTetrabenazine. Consistent with previous data both Tetrabenazine andhaloperidol were distinctly inhibitory on spontaneous locomotor activity(Satou 2001, Schaefer 1984), whereas Pridopidine displayed no sucheffects. This lack of inhibitory effects on spontaneous locomotoractivity in rats is part of the characteristic pharmacological profileof Pridopidine (Ponten 2010).

The pharmacological effect of Pridopidine at dopamine D2 receptors waspresent also when co-administered with Tetrabenazine. The neurochemicalanalysis demonstrated that all three compounds tested produced a dosedependent increase in striatal DOPAC, reaching around 250-300% ofcontrol levels at the top doses applied, in line with previous results.An increase in striatal DOPAC is a common feature of dopamine D2antagonists, as well as compounds in general producing a reduced tone atcentral dopamine D2 receptors, including partial agonists with lowintrinsic activity, and monoamine depleting drugs (Jordan, 2004;Roffler-Tarlov 1971). The increase seen in striatal DOPAC thusrepresents a core pharmacological effect of each of the compoundstested. In the interaction experiments, both haloperidol and Pridopidineproduced an additional increase in striatal DOPAC, when co-administeredwith Tetrabenazine. This strongly suggests that the primary effect ofPridopidine and haloperidol was still present in partially monoaminedepleted rats. Furthermore, despite the fact that Pridopidine reversedthe locomotor-suppressant effect of Tetrabenazine when they wereco-administered, the decrease in tissue levels of dopamine induced as asignature effect of Tetrabenazine was unaffected by Pridopidine,suggesting that it did not abolish the pharmacological effects ofTetrabenazine as such.

Overall, the typical neurochemical effects of all three compounds onDOPAC, but also dopamine levels were present throughout the studiesindicating that the core effects of each compound on dopaminergictransmission were retained.

The increased Arc mRNA in cortex by Pridopidine co-treatment may help toexplain reversal of Tetrabenazine induced locomotor depression. As anadditional biomarker of relevance especially for the differentiation ofPridopidine and haloperidol, Arc mRNA was measured in the frontal cortexand the striatum. Arc is an early gene associated with synapticactivation and NMDA receptor signalling, and has previously beenreported to increase in the striatum in response to several dopamine D2antagonists, as well as dopaminergic stabilizers. However there are noprevious reports on the effects of Tetrabenazine on Arc gene expression.As demonstrated in the examples, Tetrabenazine induced a significantincrease in striatal Arc. Albeit somewhat smaller in magnitude than theeffects of Pridopidine and haloperidol, this effect may be related toreduced striatal dopamine transmission also in Tetrabenazine treatedanimals. As was the case for DOPAC, both Tetrabenazine and Pridopidineproduced similar effects on striatal Arc in naive as in Tetrabenazinetreated rats.

In the frontal cortex, Tetrabenazine reduced Arc gene expression dosedependently, with significant effects at and above the dose used for theinteraction experiments. The dose response studies of Pridopidine andhaloperidol, demonstrated a dose dependent increase in frontal cortexArc gene expression by Pridopidine, but no effects of haloperidol. Theability of Pridopidine to increase frontal cortex Arc gene expressionwas also evident in Tetrabenazine treated rats. Thus, thispharmacological effect, which distinguishes Pridopidine from haloperidoland other classic dopamine D2 antagonists, was maintained upon partialmonoamine depletion. It is conceivable that it represents some degree ofcortical synaptic activation that could contribute to the ability ofPridopidine to counteract the behavioural inhibition in Tetrabenazinetreated rats. In support of this interpretation, Pridopidine has beenshown to increase firing of spontaneously active pyramidal cells in, thefrontal cortex.

While the examples clearly indicate that the effects of Pridopidine areretained when Pridopidine is co-administered with Tetrabenazine, thecombination of Pridopidine and Tetrabenazine did not give rise to anysigns of adverse effects. In contrast, combining haloperidol andTetrabenazine produced pronounced behavioural depression, which wouldsuggest a risk of excessive anti-dopaminergic motor side effects withsuch a combination in humans, in line with current recommendations oncaution regarding co-treatment of patients with Huntington's diseasewith Tetrabenazine and neuroleptic drugs.

Summary of Dopamine Levels in Striatum

The effects of the different treatments on striatal tissue levels ofdopamine are given in Table 1. Tetrabenazine induced a dose dependentreduction in striatal dopamine. At the dose used in the interactionexperiments, 0.64 mg/kg, Tetrabenazine reduced striatal dopaminesignificantly, reaching approximately 50% of vehicle control group mean,throughout the studies performed. Pridopidine and haloperidol bothproduced smaller decreases in striatal dopamine, at the highest dosestested. In the interaction experiments, the effect of Tetrabenazine onstriatal dopamine was essentially unaffected by cotreatment withPridopidine or haloperidol.

In summary, Pridopidine reversed the behavioural inhibition induced bythe monoamine depleting compound Tetrabenazine, while retainingPridopidine's core neurochemical effects related to dopamine D2 receptorantagonism. Thus, the locomotor depressant effects of Tetrabenazine arealleviated by Pridopidine, despite that the tone at striatal dopamine D2receptor is further reduced when Pridopidine is administered in additionto Tetrabenazine. Pridopidine also reversed the decrease in frontalcortex Arc gene expression induced by Tetrabenazine. Tentatively, thisreflects an activation of cortical neuronal activity that mightcontribute to the locomotor stimulatory effects of Pridopidine inpartially monamine depleted, hypoactive rats.

TABLE 3 Primer and probe sequences for measuring expression of Arc and two reference genes Activity- Hypoxanthineregulated phosphoribosyl gene transferase Cyclophilin (Arc) (HPRT) AGenBank U19866 AF001282 M19533 accession  number Primers  (5′-3′) SenseGGAGTTCAAG AGGGATTTGA CTGGACCAA AAGGAGTTTC ATCATGTTTG ACACAAATGAntisense CCACATACAG CTGCTAGTTC ATGCCTTCTT TGTCTGGTA TTTACTGGC TCACCTTCProbe CCGCTTACGCC TGTAGATTCAACTT TTGCCATCCAGC AGAGGAACT GCCGCTGTCCACTCAGT Dye 5′-FAM 5′-HEX 5′-Texas red Quencher 3′-BHQ1 3′-BHQ1 3′-BHQ2Product   149 121 100 size (bp)

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1. A method of treating a subject afflicted with a movement disordercomprising periodically administering to the subject an amount ofTetrabenazine or a pharmaceutically acceptable salt thereof, and anamount of Pridopidine or a pharmaceutically acceptable salt thereof.2-49. (canceled)